The City Council will investigate why thousands of waterfront-property owners whose Big Apple homes were walloped during Hurricane Sandy now face higher property-tax assessments.

After The Post yesterday revealed the stunning insult to homeowners in hard-hit neighborhoods, Council Speaker Christine Quinn said a joint council committee will hold an emergency oversight hearing Feb. 26 to address the “startling and troubling” news.

“It raises real doubts about whether [the Finance Department] is doing enough to ensure fair and accurate assessments …” Quinn said. “As New Yorkers work to rebuild their homes and lives, we cannot allow them to be hit twice.”

Although the city’s website says the assessments reflect property values as of January 5 – more than two months after Sandy struck — a city official told the Post the assessments were made prior to the storm

Mayor Bloomberg yesterday said property values have actually increased in some hurricane-struck waterfront neighborhoods around the nation.

“Prices continue to go up in spite of these things,” he said.

But many local real estate brokers say property values in Big Apple neighborhoods affected by Sandy — such as Manhattan Beach and Coney Island in Brooklyn, the Rockaways and parts of Staten Island — have fallen due to storm damage and prospective buyers now leery of living in high-risk hurricane evacuation zones.

Property owners who oppose the hikes have until March 15 to appeal to the city Tax Commission before rates are finalized in May.